I had to replace the alternator. after market alarm system went off i tracked the wire down and disabled it. blazer seemed to run but battery got weak and locked the door without me knowing left the keys in car. had to shim the door and unlock it. now my car wont start. wont even turn over. it seems to be doing every thing it normally does just dont start. but when i shut the door the security light flashes and beeps 4 or 5 times and the headlights flash for 3 or so seconds. any clue to what to do to fix this problem